Table 2.

Data dictionary for vascular plant community composition (dataset i-a) from an ITEX warming experiment in Endalen, Svalbard.

Variable name	Description	Variable type	Variable range or levels	Units	How measured
Year	Year of sampling	numeric	2003–2015	yyyy	recorded
Site	Site as the habitat; DH = Dryas heath, CH = Cassiope heath, SB = snowbed	categorical	CH - SB		defined
Treatment	Warming treatment; CTL = ambient conditions, OTC = warmed by Open top chamber (OTC)	categorical	CTL - OTC		defined
PlotID	Unique ID as the combination of Site and number; SB-1	categorical	CH-1 - SB-9		defined
Taxon	Species name including genus and species	categorical	alectoria nigricans - unidentified pleurocarp moss sp		identified
Abundance	Estimated species abundance	numeric	1–191		recorded
FunctionalGroup	Plant functional group; graminoid, forb, dshrub (deciduous shrub), eshrub (evergreen shrub), moss, liverwort, lichen and fungi	categorical	dshrub - moss		recorded
Elevation_m	Elevation of site	numeric	80–80	m a.s.l.	recorded
Latitude_N	Latitude of site	numeric	78.183 - 78.183	Degree north	recorded
Longitude_E	Longitude of site	numeric	15.75 - 15.75	Degree east	recorded
Flag	Flagging problems in the data	categorical	Iced - Iced		recorded

The dataset contains 1,273 observations of the covers of 57 taxa in 30 vegetation plots sampled across three different habitats, over a period of 12 years. Variable names, description variable type, range or levels, units and short description is given for all variables.